The invention has been devised primarily in the context of dome-shaped projection screens. Screens of this type are typically constructed from a large number of individual screen panels secured to an external supporting frame, so that the inner surfaces of the panels form the actual projection screen surface. The panels are usually thin perforated aluminum sheets, each provided with a suitable reflective coating on its inner surface. The perforations allow sound to pass through the screen and have been found necessary to achieve acceptable acoustical performance in the theatre. In a typical theatre having a dome diameter of, say, 30 m, the screen may be constructed using 300-400 panels each having an initial size of approximately 3 m by 1 m. The panels are cut to match the configuration of the supporting frame.